Rotation patterns of a mangle-type magnetic field source optimized via covariance matrix adaptation evolution strategy with 3D finite element method
Rotation patterns of a mangle-type magnetic field source optimized via covariance matrix adaptation evolution strategy with 3D finite element method
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DOI：
10.1016/j.jmmm.2022.170315
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发表时间：
2022-12-27
影响因子：
2.7
通讯作者：
Sakuma, Hiroshi
中科院分区：
文献类型：
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作者：
Sakuma, Hiroshi
芒型磁场源提供了高度的内部可达性和易于制造和操作。使用协方差矩阵自适应演化策略研究了具有四个磁体的这种磁场源的旋转模式;然而，使用2D有限元法（FEM），其假设无限的磁体长度，导致FEM计算与实验结果之间的显着差异。因此，本研究采用三维有限元法，并与二维有限元法的优化结果进行比较。该优化旨在生成具有所需幅度和方向的均匀磁场。最高磁场的磁场角是唯一确定的，这是相同的二维有限元。零磁场的磁体角度在2D和3D FEM之间是不同的;虽然通过2D FEM获得无限变化，但是通过3D FEM仅获得两组角度。用3D FEM发现的角度是螺旋形的，其中来自磁体的北极的磁通量进入下一个磁体的南极，而不偏离到中心区域。通过测量磁体的表面磁通密度并将其用于三维有限元计算，发现结果与实验结果吻合良好。
Mangle-type magnetic field sources offer high accessibility to the interior and ease of fabrication and operation. The rotation pattern of such magnetic field sources with four magnets has been investigated using a covariance matrix adaptation evolution strategy; however, the use of 2D finite element method (FEM), which assumes an infinite magnet length, results in significant differences between the FEM calculations and experimental results. Thus, this study has adopted the 3D FEM; the optimization results were compared with those of 2D FEM. This optimization aimed to generate a homogeneous magnetic field with the required magnitude and direction. The magnet angles for the highest field were uniquely determined, which were the same as those of 2D FEM. The magnet angles for zero field were different between 2D and 3D FEMs; although infinite variation was obtained via 2D FEM, only two sets of angles were obtained via 3D FEM. The angles discovered with 3D FEM were spiral, wherein the magnetic flux from the north pole of the magnet enters the south pole of the next magnet without straying into the central region. By measuring the surface magnetic flux densities of the magnets and using them in 3D FEM calculations, the results were found to be in good agreement with those of the experiments.